I'd say compared to new XT shfters some old 5 year old LX shifters would be noticeable, how much though really depends on how sensative you. I know I have the older M760 triggers and newer LX M570 and I find they shift about even, except the LX has the dual release. Are your old shifters giving trouble or are you just have the upgrade bug? If they're giving trouble buy what you can find a deal on, LX, SLR or XT are good, if just upgraditis, get the XTs to really feel lik eit was worth it.

Unless you're rolling in cash I wouldn't bother once the old ones are working fine - my XTs are 5 years old now and working fine, they'll continue to be used until they give trouble but if it's been a while since anything new adorned your bike, then shifters aren't expensive compared to other parts. FYI some new cables will most likely improve your shifting a lot if your cables are old and it's alot cheaper than the shifters

What I would say are good places to look at upgrades/replacing if it's been 5 years is your drivetrain - rings, cassette, derailleur (pulleys), chain - as these are wear and tear items and need replacing periodically depending on how much /often you ride and in what conditions.

Originally Posted by dontbealolo@gmail.com

I think I have the upgrade bug... I feel the same way about my xtr rear derailler. It's 5 years old. The new ones look sexy

They also do instant release, where the cable is let out when you push the lever, rather than when you let go. It ends up making for more responsive shifting for sure. I'd run XT shifters and LX/SLX ders over SLX shifters and XT/XTR derailleurs.

Originally Posted by oldskoolbiker

Aside from the better mechanism found in the LX. The new XT (M770) has the following additional features:

1) Dual release -- You can release the cable with either your index finger (like you currently have) or thumb.

2) The optical display is removable, and it includes a cover to put over the hole left by removing the display.

3) 2 mounting positions on the clamp, to tweak the shift leaver positions.

4) With a simple mod, they can be converted to multi-release like the XTR. In this case you can release either one or two gears with a single shift.

I also think the SLX has all these features as well except it can't be modded to be multi-release. You may consider this shifter to save a few $$$.

I can say I've taken advantage of all of these new features of XT. However, in just raw shifting performance, there won't shouldn't be that much difference.